+++ /dev/null
-/*
- * simple arithmetic expression evaluator
- *
- * Copyright (c) 2002 Michael Niedermayer <michaelni@gmx.at>
- *
- * This library is free software; you can redistribute it and/or
- * modify it under the terms of the GNU Lesser General Public
- * License as published by the Free Software Foundation; either
- * version 2 of the License, or (at your option) any later version.
- *
- * This library is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
- * Lesser General Public License for more details.
- *
- * You should have received a copy of the GNU Lesser General Public
- * License along with this library; if not, write to the Free Software
- * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
- *
- */
-
-/**
- * @file eval.c
- * simple arithmetic expression evaluator.
- *
- * see http://joe.hotchkiss.com/programming/eval/eval.html
- */
-
-#include "avcodec.h"
-#include "mpegvideo.h"
-
-#include <stdio.h>
-#include <stdlib.h>
-#include <string.h>
-#include <math.h>
-
-#ifndef NAN
- #define NAN 0
-#endif
-
-#ifndef M_PI
-#define M_PI 3.14159265358979323846
-#endif
-
-#define STACK_SIZE 100
-
-typedef struct Parser{
- double stack[STACK_SIZE];
- int stack_index;
- char *s;
- double *const_value;
- const char **const_name; // NULL terminated
- double (**func1)(void *, double a); // NULL terminated
- const char **func1_name; // NULL terminated
- double (**func2)(void *, double a, double b); // NULL terminated
- char **func2_name; // NULL terminated
- void *opaque;
-} Parser;
-
-static void evalExpression(Parser *p);
-
-static void push(Parser *p, double d){
- if(p->stack_index+1>= STACK_SIZE){
- fprintf(stderr, "stack overflow in the parser\n");
- return;
- }
- p->stack[ p->stack_index++ ]= d;
-//printf("push %f\n", d); fflush(stdout);
-}
-
-static double pop(Parser *p){
- if(p->stack_index<=0){
- fprintf(stderr, "stack underflow in the parser\n");
- return NAN;
- }
-//printf("pop\n"); fflush(stdout);
- return p->stack[ --p->stack_index ];
-}
-
-static int strmatch(const char *s, const char *prefix){
- int i;
- for(i=0; prefix[i]; i++){
- if(prefix[i] != s[i]) return 0;
- }
- return 1;
-}
-
-static void evalPrimary(Parser *p){
- double d, d2=NAN;
- char *next= p->s;
- int i;
-
- /* number */
- d= strtod(p->s, &next);
- if(next != p->s){
- push(p, d);
- p->s= next;
- return;
- }
-
- /* named constants */
- for(i=0; p->const_name[i]; i++){
- if(strmatch(p->s, p->const_name[i])){
- push(p, p->const_value[i]);
- p->s+= strlen(p->const_name[i]);
- return;
- }
- }
-
- p->s= strchr(p->s, '(');
- if(p->s==NULL){
- fprintf(stderr, "Parser: missing ( in \"%s\"\n", next);
- return;
- }
- p->s++; // "("
- evalExpression(p);
- d= pop(p);
- p->s++; // ")" or ","
- if(p->s[-1]== ','){
- evalExpression(p);
- d2= pop(p);
- p->s++; // ")"
- }
-
- if( strmatch(next, "sinh" ) ) d= sinh(d);
- else if( strmatch(next, "cosh" ) ) d= cosh(d);
- else if( strmatch(next, "tanh" ) ) d= tanh(d);
- else if( strmatch(next, "sin" ) ) d= sin(d);
- else if( strmatch(next, "cos" ) ) d= cos(d);
- else if( strmatch(next, "tan" ) ) d= tan(d);
- else if( strmatch(next, "exp" ) ) d= exp(d);
- else if( strmatch(next, "log" ) ) d= log(d);
- else if( strmatch(next, "squish") ) d= 1/(1+exp(4*d));
- else if( strmatch(next, "gauss" ) ) d= exp(-d*d/2)/sqrt(2*M_PI);
- else if( strmatch(next, "abs" ) ) d= fabs(d);
- else if( strmatch(next, "max" ) ) d= d > d2 ? d : d2;
- else if( strmatch(next, "min" ) ) d= d < d2 ? d : d2;
- else if( strmatch(next, "gt" ) ) d= d > d2 ? 1.0 : 0.0;
- else if( strmatch(next, "lt" ) ) d= d > d2 ? 0.0 : 1.0;
- else if( strmatch(next, "eq" ) ) d= d == d2 ? 1.0 : 0.0;
-// else if( strmatch(next, "l1" ) ) d= 1 + d2*(d - 1);
-// else if( strmatch(next, "sq01" ) ) d= (d >= 0.0 && d <=1.0) ? 1.0 : 0.0;
- else{
- int error=1;
- for(i=0; p->func1_name && p->func1_name[i]; i++){
- if(strmatch(next, p->func1_name[i])){
- d= p->func1[i](p->opaque, d);
- error=0;
- break;
- }
- }
-
- for(i=0; p->func2_name && p->func2_name[i]; i++){
- if(strmatch(next, p->func2_name[i])){
- d= p->func2[i](p->opaque, d, d2);
- error=0;
- break;
- }
- }
-
- if(error){
- fprintf(stderr, "Parser: unknown function in \"%s\"\n", next);
- return;
- }
- }
-
- if(p->s[-1]!= ')'){
- fprintf(stderr, "Parser: missing ) in \"%s\"\n", next);
- return;
- }
- push(p, d);
-}
-
-static void evalPow(Parser *p){
- int neg= 0;
- if(p->s[0]=='+') p->s++;
-
- if(p->s[0]=='-'){
- neg= 1;
- p->s++;
- }
-
- if(p->s[0]=='('){
- p->s++;;
- evalExpression(p);
-
- if(p->s[0]!=')')
- fprintf(stderr, "Parser: missing )\n");
- p->s++;
- }else{
- evalPrimary(p);
- }
-
- if(neg) push(p, -pop(p));
-}
-
-static void evalFactor(Parser *p){
- evalPow(p);
- while(p->s[0]=='^'){
- double d;
-
- p->s++;
- evalPow(p);
- d= pop(p);
- push(p, pow(pop(p), d));
- }
-}
-
-static void evalTerm(Parser *p){
- evalFactor(p);
- while(p->s[0]=='*' || p->s[0]=='/'){
- int inv= p->s[0]=='/';
- double d;
-
- p->s++;
- evalFactor(p);
- d= pop(p);
- if(inv) d= 1.0/d;
- push(p, d * pop(p));
- }
-}
-
-static void evalExpression(Parser *p){
- evalTerm(p);
- while(p->s[0]=='+' || p->s[0]=='-'){
- int sign= p->s[0]=='-';
- double d;
-
- p->s++;
- evalTerm(p);
- d= pop(p);
- if(sign) d= -d;
- push(p, d + pop(p));
- }
-}
-
-double ff_eval(char *s, double *const_value, const char **const_name,
- double (**func1)(void *, double), const char **func1_name,
- double (**func2)(void *, double, double), char **func2_name,
- void *opaque){
- Parser p;
-
- p.stack_index=0;
- p.s= s;
- p.const_value= const_value;
- p.const_name = const_name;
- p.func1 = func1;
- p.func1_name = func1_name;
- p.func2 = func2;
- p.func2_name = func2_name;
- p.opaque = opaque;
-
- evalExpression(&p);
- return pop(&p);
-}
projects / synfig.git / blobdiff